This invention concerns a compass able to draw ellipses of any size, particularly capable to draw ellipses of various size by a pen rod moving one round around a compass main body.
So far known, methods used for drawing ellipses are those for drawing a concentric circle, an approximate four-centered ellipse, and an approximate eight-centered ellipse. However, they are all complicated, and in addition, a completed ellipse has to be trimmed off unnecessary lines, with the ellipse got being not exactly accurate.